2. Field of the Invention
The present invention relates to a color image processing apparatus, and in particular to such an apparatus suitable for sequential color image processing.
2. Related Background Art
For example, in a digital color copying machine, a color image has conventionally been prepared by reading color data of red (R), green (G) and blue (B), then converting the image data into digital data, subjecting the digital data to data processing and supplying the processed data to an image forming unit such as a laser beam printer, a liquid crystal printer or an ink jet printer.
This data processing has generally been conducted in parallel on the color data of red (R), green (G) and blue (B) or of yellow (Y), magenta (M), cyan (C) and black (BK).
For this reason there has been required an independent circuit for each color signal, and there has therefore also been required a large and expensive circuit structure.
Also a masking circuit, constituting a part of the color image processing circuit, has been composed of a logic circuit without a table memory, or a table memory utilizing a static random access memory (RAM) or a readonly memory (ROM). However the masking operation with the former masking circuit is only capable of simple linear conversions, while the latter structure with a static RAM is inevitably expensive in case of forming a masking table of a large capacity and is unsuitable for compactization as it requires a large area for mounting integrated circuits. Also a structure with a ROM not only requires a large area as in the case of the circuit with a static RAM but also does not accept alteration of masking data.